In the construction industry, it is necessary for workmen to transport rigid sheet construction materials such as wallboard, sheet rock and plywood from piled storage or vehicular transport to the areas of construction. Not only are these sheet materials heavy and cumbersome, they are also vulnerable to damage, and, to a certain extent, dangerous in handling. Typical or standard sizes for wall-wallboard and plywood may be in the range of four by eight feet or more.
A number of prior art devices have been provided for handling, clamping and manipulating large flat objects including plywood, fiberboard, gypsum board and the like. Even with such devices, the handling of such panels has proved to be difficult and hazardous even for two or more people, because of the necessity of simultaneously grasping the panels by the workmen, lifting, balancing the sheets in the vertical carrying position and the moving of them to the necessary construction point.
Of particular importance is the problem should one of the workers carrying the sheet material stumble, fall or temporarily have to stop. Unforeseeable, unusual circumstances encountered in transporting heavy sheet materials through buildings, up stairs or inclines, around obstacles and the like all present risk and hazard to the workers, particularly because of their vulnerability in carrying the heavy weight and being linked to the cumbersome object. Therefore, it is most desirable that the devices for engaging the sheets operate to put the entire bodies of the workmen out from under and somewhat away from the materials being carried. Additionally, the engagement of the carrying device with the sheet material should be such that shifting the angle of the sheet or the like will not disengage it from the sheet or let the sheet slip from the engagement.